Candidate: Dr. Thor Wagner is a senior fellow in Pediatric Infectious Diseases at the University of Washington. His long-term goal is a career in pediatric patient-orientated HIV research. Environment: Dr. Wagner has proposed mentorship from an established pediatric HIV researcher, collaboration and consultation with various local experts, as well as a comprehensive didactic curriculum, that takes advantage of the rich academic HIV research community in Seattle, WA. Research: The hypothesis, HIV-1 replication persists at low levels in macrophages during effective antiretroviral therapy, will be addressed by three aims: (1) evaluate HIV-1 in induced sputa, which is rich in macrophages, for genetic evidence of viral replication over time; (2) determine the relative rate of viral replication in sputa macrophages compared to lymphocytes; (3) explore the relative activity of different antiretroviral regimens, including those with and without drugs that appear to be more active in macrophages, on measures of viral replication in sputum samples. In Aim 1, multiple single-genome HIV-1 sequences (SGS) derived from annual induced sputum specimens and peripheral blood mononuclear cells collected over five years from 15 children will be analyzed for evidence of replication. In Aim 2, sorting of sputa cells by flow cytometry followed by SGS will precisely define the cell types with evidence of viral replication. In Aim 3, HIV-1 replication will be gauged in sputum specimens from adults who are or are not treated with tenofovir and non-nucleoside reverse transcriptase inhibitors, which appear to be more active in macrophages. Relevance: Millions of HIV-1 infected individuals face a lifelong challenge of averting antiretroviral resistance. Persistent low-level viral replication despite antiretroviral therapy substantially increases the risk of antiretroviral resistance. Our studies will provide insight into persistent HIV-1 replication during antiretroviral therapy and whether specific drugs are more effective in suppressing viral replication in macrophages.